Invertible trawl door with resilient edge and adjustable ballasting



Feb. 1, 1966 F J LUKE-[A 3,231,998

INVERTIBLE TRAWL 130011 WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 14 Sheets-Sheet 1 INVENTOR. FRANK J. ill/(67A BYym/aw Feb. 1, 1966 F. J. LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTING 14Sheets-Sheet 2 Filed April 1, 1965 um m N E V m Fen/w :Z lull-774 mm, W

Feb. 1, 1966 LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 14 Sheets-Sheet 5 INVENTOR. FRANK 1/: JUL E774 ArroeA/e V6 Feb. 1, 1966 F. J. LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 14 Sheets-Sheet 4 INVENTOR. Fm/vx J. 111mm BY Wu Wooiooomooooo A r ray/v06 Feb. 1, 1966 J LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 14 Sheets-Sheet 5 INVENTOR. Fk'A/vk z/.' 4 UKT/l Wm@WJ Feb. 1, 1966 F. J. LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 14 Sheets-Sheets INVENTOR. FRANK J ld/(ETA BY IWail/t W V ArrOA /V Y5 Feb. 1, 1966 LUKETA 3,231,998 INVERTIBLE 'IRAWLnoon WITH RESILIENT EDGE AND ADJUSTABLE BALLASTING Filed April 1, 196314 Sheets-Sheet 7 INVENTOR.

44A 20.? 202 zz Feb. 1, 1966 F J. LUKETA 3,231,998

INVERTIBLE TRAWL EOOR WITH RESILIENT EDGE AND Filed April 1 1965ADJUSTABLE BALLASTING l4 Sheets-Sheet 8 INVENTOR. FJeAA/K J AMA/E771 Afive/V575 Feb. 1, 1966 J LUKETA 3,231,998

F. mvmwmm: TRAWL noon WITH RESILIENT EDGE AND Filed April 1, 1965ADJUSTABLE BALLASTING 14 Sheets-Sheet 9 INVENTOR. FRANK vj'. fill/(771Feb. 1, 1966 F J LUKETA 3,231,998

INVERTIBLE TRAWL 1500'R WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 l4 Sheets-Sheet l0 BYWADfiJA Feb. 1, 1966 F. J.LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1963 l4 Sheets-Sheet 11 INVENTOR. FRANK J zwzrxlINVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND 14 Sheets-Sheet 12 Feb. 1,1966 F. J. LUKETA ADJUSTABLE BALLASTING Filed April 1, 1963 INVENTOR.

mm, w

Feb. 1, 1966 F. J. LUKETA 3,231,998

INVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFlled Aprll 1 1963 14 Sheets-Sheet 15 INVENTOR. FkAA/K d: 104.1771

1 I Z Q Arraevsk Feb. 1, 1966 F J. LUKETA 3,231,998

INVERTIBLE TRAWL 1500B WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFiled April 1, 1965 14 Sheets-Sheet 14 INVENTOR. FRANK r}: 401%. 7' AINVERTIBLE TRAWL DOOR WITH RESILIENT EDGE AND ADJUSTABLE BALLASTINGFrank J. Luketa, 5567 Greenwood Ave. N., Seattle, Wash. Filed Apr. 1,1963, Ser. No. 269,454 23 Claims. (Cl. 43-9) This application iscontinuationdn-part of my copending and now abandoned application SerialNo. 210,433, and entitled, V-Door For Trawling and Bridle Therefor,filed July 17, 1962, and is also a continuation-in-part of my copendingand now abandoned application Serial No. 52,140, entitled, MultisectionDraw-l Door Construction, filed August 26, 1960.

Trawl doors of V-shaped lateral cross-section, with ballast meansprovided along the lower edge of the door, are disclosed in my priorU.S. Patent No. 2,816,385, issued December 17, 1957, and my prior U.S.Patent No. 3,048,936, issued August 14, 1962, for example. Partly toimprove hydrodynamic stability, ballasting means have been employed insuch V-doors, specifically in the component of the door making up thebottom edge thereof which skids along the sea bottom when the door is inuse. In such prior door designs, wearing away of the bottom edge of thedoor, which wear often occurs in an uneven manner, result in change ofhydrodynamic charaoteristics of the door, but especially lessens thedoors capability to stay on or hold bottom which is of the es- UnitedStates Patent sence in bottom trawling, since loss of ballast weight dueto wear necessarily lessens the weight of the door and also could changeits planing characteristics if the bottom edge wear were uneven in itsfore and aft aspect. Compensating the loss of weight to wear by theaddition of ballast weights along and just inboard of or in other wordsslightly above the lower edge of the door, as disclosed in my aforesaidPatent No. 3,048,936 is a partial solution to the problem, but does notprevent the further loss of essential ballast and potential unbalanoingof the door as a result of further wear along the bottom edge. In fact,this wearing away or attrition of the vital ballast and its attendinghighly undesirable result is a continuing problem. i

It has also been proposed, as in my aforesaid US. Patent No. 3,048,936,and in my copending application Serial No. 219,276, entitled, TrawlDoors, and filed August 24, 1962, to'make a trawl door invertible byinterchanging the components making up the respective upper and loweredges of the door. These prior arrangements for invertibility, however,involve either interchange of a relatively large number of doorcomponents, or interchange of elements, some of which are so worn as tofunction (such as for ballast) no better when relocated, so the problemgiving rise to the necessity for the interchange (eg. bottom wear) isnot satisfied unless the components are replaced. 1

A further problem with respect to bottom ba'llasted trawl doors of priordesign is that the ballasting means thereof is at least principallybuilt into the bottom edge of the door and is thus not longitudinallyadjustable of the door to compensate for varying conditions of use. Yeta further problem with respect to such prior door designs is that theballast means thereof is of a dissimilar, heavier metal (e.g. steel),while the bulk of the door was of a lighter metal (e.g. aluminum), thedissimilar metals being directly exposed so as to be susceptible toelectrolytic degradation.

Yet another disadvantage of prior door design is that the metal edgingthereof, particularly the bottom or wear edge, was formed of metal, orat least principally of metal, so as to be relatively susceptible towear when skidding along the bottom and encountering bottom obstacles.Metal, even though structurally relatively strong, is so "ice rigid :asto abrade and fracture relatively easy under scraping and high stress.It is a principal object and feature of the present invention to providea trawl door construction wherein the entire marginal edge of the doorwhich may encounter underwater obstacles and which is subjected to wearis in the configuration of a relatively large bead composed of awear-resistant relatively lightweight, resilient, cushioning materialwhich is waterlubricated, which head is composed of rubber or likeelastomeric material having comparable resiliency and wear resistance.It is a related object and feature of the invention to form therubber-like cushioning, wear resistant bead around the marginal edge ofthe door by molding the bead onto the metal door panel in a manner sothat the cushioning material is structural-1y interlocked with thepanel, as by providing a series of peripheral holes in the metal panel,through which the cushioning material injects and bondsby'intraconnection.

Another object and feature of the present invention involves thecomplete isolation of the edge components of the door affected by wearfrom the components of the door providing ballast and buoyancyfunctions. As a result of such isolation, the degree of wear generatedin the door edge bead as a result of use, even protracted use, does notchange the hydrodynamic characteristics of the door to any significantdegree; The door is thus rendered hyd-rodynamically stabilizedindependent of wear, and it is a related feature and advantage of thepresent invention that such a hydrodynamically stabilized door isconstructed so that the ball-asting means and in certain instances alsothe buoyancy means thereof is readily adjustable so that should thebot-tom edge of the door be wearing unevenly under given use conditions,the effective center of gravity of the door can be changed In thisrespect, it is important to note the significant distinction between useof compensating ballast weights in a hydrodynamically unstable doorwhere the effective center of gravity is affected by wearing away of theballast means, and the situation where, as in doors according to thepresent invention, the door is hydrodynamically stable so that adeveloping unevenness in wear along the lower edge of the door iscorrected by a selective change in the center of gravity. In the latterevent the error (i.e. improper cen-. ter of balance) which gave rise tothe uneven wear is non-recurring under given operating conditions (whichis the case when a trawler continues to operate at a customary speed anda customary towing warp scope), while in the former case the errorgiving rise to uneven ness in wear is of a recurring-nature. i Yetanother object, feature and advantage of themesent invention isto-provide a trawl door construction of an invertible nature, theinversion of which (to adapt same for port rather than starboard use, orvice versa) is simply and readily accomplished without shifting orinterchanging any marginal parts, the conversion to invert the doorsimply involving interchange of buoyancy and ballast elements andshifting of the towing warp hookup to the bridle, for example.

Still another object and feature of the present invention resides in itsuse of longitudinally and selectively adjustable ballast means, theadjustability characteristics of which render practical use of arelatively forward towing Warp hookup point in relation to the center oflift of the door (i.e. the water reaction center) when the relativelyconcentrated ballast is adjusted well forwardly on the teristics of apair of doors that permit a relatively sharp turn when trawling, withoutthe doors fouling one another (causing the termination of the tow due tomalfunction, necessitating the hauling in of the gear and the untanglingof the doors with the resulting loss of valuable fishing time), is acapability of primary importance.

Leveling of the door, and maintenance of the door in a level attitudeduring use (that is, keeping the apex line of a V-sectional door, or thebottom edge or runner of a door of any configuration horizontal whentowed), is accomplished under operating conditions by appropriateselective positioning of the longitudinally adjustable ballast means,rather than by reliance on a relatively close hookup of the towing warpanchorage point in relation to the center of lift, as is the case withthe door design disclosed in my aforesaid US. Patent No. 3,048,936. Inthis respect, however, it is also to be noted that the improved bridleand towing warp hookup arrangement of the present invention retains allof the advantages of the earlier bridle arrangement in terms ofutilizing a haul point slightly below the center line of the door torender the bottoming force a function of speed, i.e. the door ismaintained in a substantially tilted attitude, laterally considered, sothat the downward thrust on the upper panel portion is greater than theupward thrust on the lower panel portion.

A further object and feature of the present invention involves improvedsweep line and towing warp hookup arrangements, including use ofenlarged, rounded saddles forming a part of or placed contiguous to therear edge of the door and receiving flexible eyes which are in turnconnected to or form a part of the sweep lines, such saddles and eyesbeing relatively movable so that the sweep lines are at all timesstraight when under tension and pull points between the door and thesweep lines are substantially coincident with the rear edge of the door.As a related object and feature of these hookup arrangements, insulatingmeans of rubber or like material are employed between the saddle andline eye core or between the door and saddle so that these componentsare not susceptible to electrolytic degradation even though constructedof dissimilar metals.

Yet another important feature and advantage of trawl doors according tothe present invention is that the rubber or like door edging around allportions of the door coming into contact with the sea bottom engage andrun over the bottom much more silently than when the door is metaledged. A silent running door, such as here presented, is much lesslikely to scare away the marine life in the path of the net being hauledand is therefore capable of significantly improving the catch. As arelated object and advantage of the present door construction, certainforms of the sweep line and towing warp hookup arrangements for the doorinclude flexible eyes or like components whch are sheathed with rubberor like material at points of contact with the door so as to be moresilent (i.e. not creak) when the door is in use.

A further important feature and advantage of the cushioning,wear-resistant edge characteristic of doors according to the presentinvention is that the rubber or like edge thereof serves as a bumper andminimizes the likelihood of damage to the trawling vessel or to the doorhandling equipment thereof when the door is being hauled in or is onboard the trawling vessel, as for stowage or rerigging.

These and other objects, features, advantages and characteristics of thepresent invention will be apparent from the following description ofcertain typical and therefore non-limitive embodiments thereof, whereinlike letters and numerals refer to like parts, and wherein:

FIG. 1 is a small scale, somewhat fragmentary isometric view of atypical bottom trawl net, with the sweep lines thereof being spread andtowed by trawl doors incorporating certain features of the presentinvention;

FIG. 2 is an isometric view on an enlarged scale of the port door shownin FIG. 1, with a portion of the ballast assembly broken away forclarity of illustration, the view being of the trailing or posteriorside of the door;

FIG. 3 is an isometric view of the port door shown in FIG. 2, as viewedfrom the leading or anterior side thereof, with a portion of thecushioning and shafing cut away to show constructional detail;

FIG. 4 is a side view of the door shown in FIGS. 2 and 3, taken from thetrailing side thereof;

FIG. 5 is a view in lateral cross-section and on an enlarged scale ofthe door shown in FIG. 4 taken substantially along line 55 thereof;

FIG. 6 is an enlarged fragmentary isometric view, taken substantiallyalong line 66 of FIG. 2, with portions of the cushioning and shafingbead broken away to show constuctional detail in the area of the uppersweep line saddle;

FIG. 7 is an isometric detail view on an enlarged scale; showing atypical segment of the panel edge and the cushioning and chafing beadmolded thereon;

FIG. 8 is a fragmentary isometric view of the trailing side of the doorshown in FIG. 2, with an exploded showing of the ballast capsulepositioning and retaining bolts, and also showing a typical ballastcapsule positioning device;

FIG. 9 is an exploded isometric view of the ballast capsule,illustrating the construction thereof;

FIG. 10 is a fragmentary isometric view of a modified form of sweep linehookup arrangement characteristic of the invention;

FIG. 11 is an enlarged detail view of the sweep line connection assemblyshown in FIG. 10, taken substantially along line 1111 thereof withcertain parts further broken away to show constructional detail;

FIG. 12 is a fragmentary isometric view of a modified form of towingwarp hookup assembly;

FIG. 13 is a fragmentary plan view, similar to the isometric view ofFIG. 10, showing a further modified form of sweep line hookuparrangement, involving an elongated slot in the door panel just inboardof the rear marginal edge thereof, the view being with certain parts incrosssection for clarity of illustration;

FIG. 14 is a cross-sectional view of the sweep line hookup arrangementshown in FIG. 13, taken substantially along line 14,-14 thereof;

FIG. 15 is a fragmentary plan view of a further modified form of sweepline hookup arrangement, involving a hole in the door panel just inboardof the rear marginal edge, and use of a flexible eye joined to the sweepline;

FIG. 16 is a cross-sectional view of the sweep line hookup arrangementshown in FIG. 15, taken substantially along line 1616 thereof;

FIG. 17 is a schematic side view of a door incorporating an adjustableballast means such as shown in FIG. 8, the schematic showing of FIG. 17illustrating an operating condition where the center of gravity of thedoor is too far aft so that the rearmost portion of the lower marginaledge is consequently receiving the most wear;

FIG. 18 is a schematic View similar to FIG. 17, illustrating the mannerof adjustment of the ballast means to correct the uneven wear occurringin FIG. 17;

FIG. 19 is a schematic view similar to FIG. 17, illustrating theoccurrence of uneven wear in the forward portion of the lower edge ofthe door;

FIG. 20 is a schematic view showing the manner of correction of the wearcondition shown in FIG. 19;

FIGS. 21-24 are isometric views illustrating the disassembly of a portdoor and reassembly thereof as a starboard door to illustrate theinvertibility of the form of door which is illustrated at FIG. 2, FIG.21 showing the door in the form used as a port door, FIG. 22illustrating by exploded view the removal of the ballast and buoyancyassemblies and the top for bottom reversal of the door, FIG. 23illustrating by exploded view the reassembly of the buoyancy and ballastassemblies onto the door panel, and FIG. 24 illustrating the reassembleddoor ready for use as a starboard door;

FIG. 25 illustrates in lateral cross-section a modified form of doorutilizing the cushioned edge andutilizing buoyancy and ballastassemblies essentially like those employed in the form of door shown inFIG. 2, the door panel in the form of door shown in FIG. 25 being flat;

FIG. 26 is another form of door arrangement characteristic of theinvention, the door panel in this instance being flat, the adjustableand invertible ballast means being in the form of stacked bars, and thebuoyancy means being a series of trawl net floats;

FIG. 27 is a typical view in lateral cross-section and on an enlargedscale of the trawl door shown at FIG. 26;

FIG. 28 is a fragmentary detail view on a further enlarged scale,showing further constructional detail with regard to the buoyancy meansof the form of door shown in FIG. 26, with certain parts broken away forclarity of illustration;

FIG. 29 is an isometric detail view of a float clamp as employed inFIGS. 26-28;

FIG. 30 is an isometric view showing the leading face of yet anotherform of door incorporating certain features of the present invention;

FIG. 31 is an isometric view ofthe door shown at FIG. 30 showing thetrailing face thereof;

FIG. 32 is a plan view showing the leading face of the door shown atFIG. 30;

FIG. 33 is a View in lateral cross-section of the door shown at FIG. 30,taken substantially along line 33-33 thereof;

FIG. 34 is a detailed sectional view of anchorage eyes takensubstantially along line 3434 of FIG. 33;

FIG. 35 is a fragmentary, isometric view with certain parts broken away,illustrating a modified form of canister type-ballast means having aremovable end cap and a plurality of ballast weights;

FIG. 36-is a view in side elevation and in section, showing a portion ofa ballast canister shown in FIG. 35, the sectioned portions thereofbeing taken substantially along line 3636 of FIG. 37;

FIG. 37 is a view in lateral cross-section of the canister shown at FIG.36, being in part taken substantially along line 37--37 thereof;

FIG. 38 is an exploded isometric view on a further enlarged scale,showing additional detail with respect to the removable end cap of theballast canister shown at FIGS. 35-37;

FIG. 39 is a fragmentary view in side elevation showing a modified formof door and sweep line hookup arrangement, involving alternatively usedsaddles;

FIG. 40 is a view similar to the view of FIG. 39, showing the sweep linehookup arrangement used in connection with the door shown at FIG. 39,with the door inverted;

FIG. 41 is a fragmentary View in side elevation, with a portion brokenaway for clarity of illustration, of a modified form of resilient edgingand edging mounting arrangement;

FIG. 42'is a view in lateral cross-section, taken substantially alongline 42-42 of FIG. 41;

FIG. 43 is an isometric fragmentary view further illustrating the typeof resilient edging illustrated at FIGS. 41 and 42, and further detailas to the edging-to-panel interconnection;

FIG. 44 is an exploded isometric view similar to FIG. 43, furtherillustrating the edging mounting arrangement; Y FIG. 45 is a sideelevational view of a corner portion of a door incorporating the type ofedging illustrated at FIGS. 41-44;

FIG. 46 is a view in side elevation of a modified form of resilientedging and panel-to-edging mounting arrangement;

FIG. 47 is an isometric view on an enlarged scale further illustratingthe form of edging and mounting arrangement illustrated at FIG. 46;

FIG. 48 is a view in side elevation and in section, further showing thepanel and edging shown at FIGS. 46 and 47; i i

FIG. 49 is a view in lateral cross-section, taken substantially alongline 49-49 of FIG. 48;

FIG. 50 is an isometric detail view of yet another form of constructioninvolving a resilient edging mounted to a panel edge;

FIG. 51 is a view in side elevation of the panel edge and resilientedging shown at FIG. 50, with a portion thereof broken away for furtherillustration;

FIG. 52 is a view in lateral cross-section taken substantially alongline 52-52 of FIG. 51;

FIG. 53 is a fragmentary isometric view of still another form of paneledge and rubber edging arrangement;

FIG. 54 is a view in side elevation of the modified form of theinvention shown at FIG. 53, with certain portions broken away to showinterior detail;

FIG. 55 is a view in lateral cross-section taken substantially alongline 5555 of FIG. 54; and

FIG. 56 is an isometric detail view of one of the embedded anchormembers shown in FIGS. 53-55.

Turning to a more particular consideration of the accompanyingillustrations, FIG. 1 serves to illustrate a typical environment of useof trawl doors according to the invention. The showing of FIG. 1 is of atypical bottom trawling net comprised of a codend C closed by a purseline PL and joined to a funnel F from the forward end of which wings Wdiverge, the wings W being arranged bet-ween an upper float line FL anda lower ground line GL. The ends of the float line FL and ground line GLat the starboard side of the net are connected to sweep line means,involving either a single sweep line or an upper and lower pair of sweeplines SL (as shown) which in turn lead to and are hauled by a starboarddoor SD which planes out to starboard and along the sea bottom as thedoor is towed bytowing warp T led from the trawling vessel, not shown.Similarly, the port ends of float line FL and ground line GL connect tosweep line means such as sweep lines SL led to a port door PD hauled bya towing warp T towed by the trawling vessel.

In general the present invention pertains to various constructionalarrangements characteristic of the trawl doors SD and PD. In the firstdoor embodiment illustrated, the port door PD being selected by way ofexample to show constructional arrangement and detail, it will beobserved in FIGS. 2-9 that the door comprises a metal panel 40, which inlateral cross-section is of a dihedral or shallow V configuration withsymmetrical panel portions above and below an apex line or crown, theupper and lower portions of the panel 40 being swept back substantiallyon its leading face, the panel portions having an angle therebetween ofabout on the trailing face of the door. Panel 40 is preferably ofaluminum construction and may be either cast (e.g. in the case ofrelatively small doors) or fabricated from sheet stock (e.g. in the caseof relatively large doors). The forward portion or nose of the door isof a rounded configuration and the trailing edge thereof is squared off,with slightly rounded corners; however, as will be apparent, theconfiguration of the door outline can be varied considerably as desired.

A rounded, marginal edge or head of cushioning, abrasion resistant,lightweight material such as cured rubber extends around the nose andsides of the panel, as shown at 42, 44, 46, 48, 50. This marginal edgeis preferably although not necessarily continuous, and is often simplyhereinafter termed the wear edge or rubber edge. For purposes ofparticular reference to certain portions of the rubber or like marginaledge in the following discussion, various portions thereof have beenseparately designated in the accompanying illustrations, edge .portion42 being the portion extending around the rounded upper. rear corner ofthe. panel 40, side edge portion 44 being the straight portion along theupper edge of the panel 40, edge portion 46 being the curved portionthereof around the nose of the panel 40, side edge portion 48 being thestraight portion along the bottom of the door panel 40, and edge portion50 being that portion around the rounded lower rear corner of the panel40. In addition to the edge portions indicated, the door marginal edgefurther comprises a rear edge 52 which is also formed of a rounded,lightweight, cushioning material and is suitably of identicalcross-section and constituency as the edge portions 4250.

The rubber or like edging 4252 is suitably atfixed to the edge of thepanel 40. A particularly advantageous manner of interconnecting theedging with the panel is illustrated in the accompanying figures andinvolves fabrication of the panel 40 with a series of near edge holes,certain of which are indicated at 54 in FIGS. 3, 6 and 7, for example,with the edging 42-52 being pressure molded and cured in situ around thepanel 40 so as to intrabond through the holes 54 and thereby bestructurally integrated with the panel 40 by mechanical interconnection.The peripheral edge of the panel 40 is preferably also cross-sectionallyenlarged to improve the panel-to-edging interconnection and to present ablunt edge to prevent interior cutting of the rubber as the resilientedge flexes in use, such as indicated at 56.

As used herein, the terms resilient, rubber-like and resilient,rubber-like material, as applied to edging 42 52 for example, refer to amaterial that has high extensibility and forcible quick retractionrather than to hard rubber. This definition is in accordance with thedefinition of rubber as set forth on pages 2 and 3 of Engineering Usesof Rubber, edited by A. T. McPherson and A. Klernin, published 1956 byReinhold Publishing Corp., New York, New York.

As best shown in FIGS. 2 and 6, th rear edge areas 58, 60 of the panel40 between the respective ends of the edging portions 42, and the endsof edge portion 52 are of a cylindrical configuration andcross-sectionally identical to the edge portions 42, 50, 52. However,for purposes of mechanically strong interconnection of the door panel 40to the sweep lines SL, these edge portions 58, are constructed of metal(being preferably integrally formed with the panel 40) and provide whatmay be termed saddles or saddle means which serve as anchor points forthe flexible eyes 62 at the ends of the sweep lines SL, the portions ofthe panel 40 immediately inboard of the saddle means 58, 60 being cutout and preferably provided with enlarged edge beads 64, 66 to minimizewear on the flexible eyes 62. Placement of the saddle means 58, 60coaxially of the adjacent edging portions 42, 50, 52 places the lines ofpull of the sweep lines in substantially intersecting relationship withthe rear edge of the door. Further, the rounded surface of the saddlemeans 58, 60 provide that the flexible eyes 62 are free to move in anyattitude angularly with respect to the door so that the door has aconsiderable freedom of movement with respect to the sweep lines hauledby the door.

One of the flexible eyes 62 is illustrated on an enlarged scale in FIG.16. As shown in said FIG. 16, the flexible eye 62 comprises a steelcable core 68 onto the ends of which swage socketed eyes 70 areinstalled. Eyes 70 receive a connecting bolt 72 passed through thelooped end of sweep line SL. The flexible cable 68 and the swage socketsof eyes 70 are covered by a rubberlike wear resistant, insulating sheath74. The insulation provided by sheath 74 isolates the aluminum doorpanel 40 and the steel members such as cable 68 used in the sweep linehookup from electrolytic degradation. The sheath 74 further functions topresent a resilient thrust bearing surface to the saddle and thusminimizes rigging noise when the door is in use.

The bridle assembly to which the towing warp T is anchored is mounted onthe leading face of the door and in the preferred form of door shown inFIG. 3 comprises a forward leg or strut '76 and upper and lower rearlegs 78, 80, respectively. The trawl door illustrated employs a rigid,three-legged form of bridle arrangement; however it is to be understoodthat any suitable type of bridle can be employed, such as the bridlearrangement disclosed in my aforesaid U.S. Patent No. 3,048,936 andemployed in the modified form of the present invention as illustrated inFIGS. 30-34 and discussed below, and such as the form of bridlearrangement disclosed in my prior US, Patent No. 2,816,385, simply byway of further examples. In the specific form of bridle assembly shownat FIG. 3, the bridle assembly is preferably fabricated or cast ofaluminum and the forward leg 76 thereof is attached as by bolt 82 to thepanel 40 at a point laterally centrally placed on the panel and wellforward of the center thereof, longitudinally considered. A stiffeningboss 84 on the trailing side of the panel 40 (FIG. 2) receives the bolt82. stiffening ribs 86, 88 extend laterally of the panel 40, and theafter stiffening rib 88 includes laterally offset bosses 90 and 92 (alsonote FIG. 4) receiving respective anchor bolts 94, 96 for the bridlerear legs 78, 80, the forward face of panel 40 being also provided withtwo laterally offset bosses 98, 100 providing coplanar faces for theends of the respective legs 78, 80.

In the manner characteristic of the bridle arrangements disclosed andclaimed in my aforesaid US. Patent No. 3,048,936, the bridle arrangementshown at FIG. 3 is hooked up to the towing warp T at a point downwardlyoffset from the center plane of the panel 40 in order that the door inuse is tilted substantially outwardly so that the water thrust againstthe upwardly facing panel portion is greater than the thrust against thedownwardly facing panel portion (i.e. tilted in the manner shown in FIG.12 of said Patent No. 3,048,936). For this purpose, when the door isbeing used as a port door as shown at PEG. 3, the hookup to the towingwarp T is to an anchor eye 102 laterally offset below (as shown in FIG.3) the horizontal center line (designated C/L) of the door, the specifichookup shown being by means of an insulated flexible eye 62 (which isconstructionally like and in fact interchangeable with the sweep linehookup flexible eyes 62 previously discussed), so that there isinsulation from electrolytic degradation as between the aluminum bridleassembly and the steel towing warp T. A reversely offset :anchor eye 104is also provided for use as the hookup point for the towing warp T whenthe door is inverted for use as a starboard door, as more fullydiscussed below in connection with FIGS. 21-24.

The bridle assembly shown at FIG, 3, for example, offers variousadvantages over prior bridle assemblies, in that it stands outsubstantially from the anterior face of the panel 40, and has no movingparts so does not wear at points of interconnection. 102, 104 arestrongly braced and readily accessible and the entire 'bridle assemblyis hydrodynamically clean.

As earlier indicated, it is a significant feature of the trawl doorshere presented that the ballast means of the.

door is separate from the portion of the door encountering wear. It isalso a feature of certain of the ballasting means here presented thatthe ballasting means is adjustable longitudinally of the door tosuitably shift the center of gravity thereof so that the wear on thedoor lower edge is evened. It is a further feature of certain of thepresent door arrangements that the ballasting means is used inconjunction with a laterally opposed buoyancy means, the ballast meansand buoyancy means being interchangeable so that the door can be readilyinverted for use on the opposite wing of a net.

All of these features pertain to the form of door illustrated at FIGS.19. More specifically, this form of door comprises a ballasting means,generally indicated at 110, and a buoyancy means, generally indicated at112. Each of the means 110, 112 is externally configured like the otherand quickly attachable and removable from the trailing edge of the doorinboard of the edges thereof. In the form shown, the ballast meanscomprises a generally cylindrical, rounded end canister 114, bolted foreand aft to the stiffening ribs 86, 88, the bolting ar- Further, itsanchor eyes rangement involving external lugs 116, 118 on the canister114 through which respective bolts 120, 122 pass. Suitable holes toreceive said bolts are provided in the stiffening ribs 86, 88, and saidstiffening ribs are preferably recessed to cradle the canister 114 whenin attached position, the cradling contour thereof being indicated at124, 126, respectively (see FIGS. 22 .and 23). Similarly, the buoyancymeans 112 comprises a sealed canister 128 of generally cylindrical,rounded end configuration, provided with respective fore and aft lugs130, 132, attached by bolts 134, 136 through holes in the ribs 86, 88 soas to be cradled against the respective recessed portions 138, 140 ofthe stiffening ribs 86, 88.

As best seen in FIGS. 2 and 8, the ballast means 110 comprises a movableweight 142, suitably in the general configuration of a cylinder of adiameter to more or less snugly fit within the ballast canister 114. Asshown in the exploded detail View of FIG. 9, the weight 142 can suitablybe fabricated from an aluminum can 144 in which molten lead is poured toform a lead slug 146, the slug 146 being sealed within the can 144 'byan aluminum cap 148 suitably sealed into the mouth of the'can 144, as

by welding, the prevent electrolytic action between the lead andaluminum when submerged in water. The re sulting ballast weight 142 isplaced within the ballast canister 114 during the assembly of thecanister (i.e. before one rounded end cap thereof is welded in place) sothat the ballast canister 114 and ballast weight 142 present a compact,self-contained ballasting unit.

, Positioning of the ballast weight 142 longitudinally within thecanister 114 (and accordingly longitudinally of the door when thecanister 114 is in plate) is facilitated by end access holes 150 in theballast canister 114, through which a positioning rod 152 can beinserted (note FIG. 8) to change the position of the ballast weight 142.

Multiple rows of holes, which are indicated at 154, extend radially intothe canister 114 to .allow flooding of the canister. Selected opposedpairs ofsuch holes 154. also serve to receive a pair of positioningbolts 156 which secure the ballast weight 142 in desired position withinthe canister. Preferably, the bolts 156 are tightened sufficiently topinch the canister 114 against the weight 142 so that the latter isfirmly retained without relative movement in the canister. FIGS. and 11serve to illustrate a slightly modified form of saddle arrangementforconnection of the sweep lines SL to the rear edge area of the door. Asshown in FIGS. 10 and 11, this arrangement involves a modified form ofsteel saddle 160, the return bend portion of which is encircled by theeye of the sweep line SL. The forward ends of saddle element 160 areretained by a bolt 162 passing through a boss 164 just forward of therear edge of the panel 40, with flanged nylon or like inserts 166, 168serving to insulate the saddle 160 from the door panel 40'. The form ofsweep line hookup arrangement shown at FIGS. 10 and 11 has an advantagesimilar to the earlier discussed sweep line hookup arrangement in thatthe sweep line point of thrust is placed substantially at the rear edgeof the door, and is further advantageous from the point of view that thefull extent of the rubber or like edging provided at the rear edge ofthe door panel can be continuous, as indicated at 52'. FIG. 12illustrates a slightly modified aluminum bridle construction. In thisarrangement, the selected anchor eye 102' or 104' provided in slightlyoffset relation from the center line CL in the juncture area of forwardlegs 76 and rear legs 78, 80 is connected to the towing warp T by meansof a steel shackle 160' which connects to the selected eye 102 or 104'in like manner as the saddle 160 connects to the holed boss 164 shown inFIG. 11, i.e. by a bolt 162 which is insulated from the bridle eye bymeans of insulative, nylon or like flanged inserts, the edge of one ofsuch inserts being shown in FIG. 12 at 168'. As will be apparent, thesteel shackle 160' and its bolt 162 are thus insulated from electrolyticdegradation.

FIGS. 1.3 and 14 illustrate a further modified form of sweep line hookuparrangement wherein the door panel 40" is provided with a continuousrear edge 52" and a longitudinally elongated slot is provided in thepanel 40" just inboard of the rear edge. Slot 170 is provided with anenlarged edge bead 172, the elongated nature of the slot 170 being toenable installation of a shackle 174 (the manner of installation ofwhich is shown in phantom in FIG. 14). The shackle 174 in its returnbend portion is provided with a rubber or like sheath 176 which cushionsand insulates the bearing engagement of shackle 174 with the rearportion of the enlarged slot edge 172, the latter functioning as asaddle in this arrangement in that its relation to the end of the sweepline SL through shackle 174 is directly comparable to that of the saddleelements 58, 60 in bearing engagement with the flexible eyes 62 at theends of the sweep lines, as discussed in the form of sweep line hookupshown at FIGS. 2 and 3, for example.

As will be apparent in FIGS. 13 and'14, the shackle 174 is provided witha bolt 178 and spool 180 to connect same with the eye at the end of thesweep line SL. To facilitate the installation of shackle 174, the rubberor like rear edging 52" is provided with inset or cut out portions 182,184 immediately rearwardly of the slot 170.

FIGS. 15 and 16 illustrate yet another variation in sweep line hookuparrangement, the arrangement in this instance involving a rubber or likecovered flexible eye 62 of the type previously discussed, the eye 62passing through a hole 186 in panel 40" at a point just inboard of therear edging 52 of continuous rubber or like construction, the hole 186being provided with an enlarged edge 188 serving in its rear portion asthe saddle element for the flexible eye 62.

FIGS. 17-20 collectively present schematic side views of a doorcharacteristic of the invention (the type shown at FIGS. 29 beingselected for purposes of illustration), and serve to illustrate certainconsiderations with respect to the adjustable ballast means afforded bythe invention. In FIG. 17, a condition of use is illustrated wherein aport door PD is riding predominantly nose up so is receiving undue wearon the rear part of the bottom edge. Excessive wear at the .rear of thebottom edge is of course indicative of the operational center of balanceof the door, as influenced in part by the upward moment arm exertedbythe towing Warp T, being too far aft, and the indicated selectiveadjustment is to move the ballast weight 142 from the position shown inFIG. 17 to the position thereof shown in FIG. 18.

The converse condition where the door bottomsedge is receiving excessivewear in its forward portion is illustrated in FIG. 19. Upon'encountering this condition, the corrective adjustment is to move theballast. weight 142 to a more rearward position within a ballastcanister 114, as indicated at FIG. 20.

As will also be understood in the art to which the. invention isaddressed, the attitude of the door when planing along the sea bottom issubstantially a function of bottom depth and length of towing warp (i.e.scope),. and also a function of towing speed. Operational variation ofany of the relevant factors aifectingthe planing attitude of the doorcan affect the manner in which the door rides along the sea bottom.Since it is oftentimes desirable or necessary to accommodate thetrawling gear to changes in trawling speed and/or changes in towing warpscope, it is very desirable to have readily adjustable ballasting meansto compensate for changes in manner of use of the door, and it is afundamental object and purpose of the present invention to provide atrawl door having such capabilities. Furthermore, since a door in orderto be produced at reasonable cost should be standardized as much aspossible, this inherent leveling capability is essential. As a case inpoint, in the fleet of several thousand shrimp trawlers in the Gulf ofMexico, there are for various reasons, wide variations in towing speeds,towing warp scopes, and also in net sizes and types. The presentinvention enables each skipper to adjust his door ballasts to suitrequirements, simply by changing postion of the ballast weight on eachdoor, and/or using interchangeable ballast canisters equipped withlighter or heavier weights, as desired.

In regard to the ballasting weight itself, it will be noted in the doorof FIGS. 2-9 that the weight 142 is of compact length and of densematerial (lead); this makes for a much broader range of effectiveleveling capability. This capability gives rise to the possibility ofdesigning a self-leveling door with a level-state sensor controlling theoperation of a ballast positioning mechanism. The compact ballast weightof this invention is highly advantageous in such an arrangement,attaining quick response as well as a wide range of leveling response.

Another important feature of the trawl doors here presented is theircapability of being readily inverted without necessity for changing anyedge components and without having to make any corrective adjustment asto ballasting. The manner of inverting the form of door illustrated atFIGS, 2-9 is shown by FIGS. 21-24 (simply by way of example). I11 FIG.21, the door comprising panel 40 is configured as a port door PD, withthe ballast means comprising canister 114 being in a lower position (asshown) and the buoyancy canister 128 in an upper position, the marginaledge 48 being the bottom engaging edge and the marginal portion 44 beingthe upper edge. As suflicient wear develops along the lower edge 48 ofthe door PD to necessitate inverting thereof, the respective ballast and buoyancy canisters 114, 128 are removed by removal of the variousbolts 120, 122, 134, 136, the removed condition of the canister andbolts being illustrated in FIG. 22. The door PD is then inverted, asindicated at I in FIG. 22 so that (as in the inverted position shown atFIG. 23) the worn edge portion 48 becomes the upper edge and the unwornedge portion 44 becomes the lower edge. The ballast canister 114 is alsoreversed end for end as indicated at R, and it and the buoyancy canister128 are then reinstalled on the ribs 86, 88 in the manner shown at FIG.23, following which the reassembled door (as in FIG. 24) is ready foruse as a starboard door (and so designated SD in FIGS. 23 and 24). Aswill be noted, the buoyancy and ballast distribution of the starboarddoor (FIG. 24) is the same as the buoyancy and ballast distribution thatexisted in the port door PD (FIG. 21) in that the ballast and buoyancycanisters 114, 128 have changed positions and the centers of buoyancyand gravity have been laterally reversed but have not been shiftedlongitudinally of the door.

The door of this invention has cost saving and convenience factors ofconsiderable importance since only one type of door need bemanufacturedtl1e invertibility of the door permitting one type of doorto serve either side.

Of equal importance, the vessel need carry only one door I as a spare incase of loss or damage of either standard equipment door while at sea,and the fact that the door ballast can be readily detached also assistsin handling the heavy door for storage or replacement.

FIG. 25 illustrates a lateralcross-section of a modified form of doorconstruction incorporating on a flat panel 190 a rubber or like marginaledge 44, 48 and canister type ballasting and buoyancy means similar tothe ballast canister 114 and the buoyancy canister 128 of the form ofdoor earlier discussed. The ballast and buoyancy means comprising thecanisters respectively indicated at 114 and 128, are constructedidentically to the canisters 114 and 118 except that they are mountabledirectly on the face of the panel 190, suitable respective lugs 192 and194 being arranged on the canisters 114' and 128' to abut the panel 190and be secured thereto by respective bolts 196, 198. As will beapparent, the canisters 114 and 128' are invertible in the same manneras the canisters 114 and 128 by the same procedure as illustrated inFIGS. 21-24, being removable from the panel 190 and reinstallable 12thereon in laterally reversed position by means of the respective bolts196, 198.

FIGS. 26-29 illustrate a further modified form of door constructionaccording to the present invention. This door comprises a flat panel 200with rubber or like edging portions 42A, 44A, 46A, 48A, 50A, 52Aextending continuously around the edge of the panel 200. The buoyancymeans in the door illustrated at FIGS. 26-29 comprises a plurality ofindividual floats 202, suitably of a type conventional per se andcommonly employed as trawl net floats, each of the floats 202 beingclamped to one side of the panel 200 by means of a clamping member 204(shown in enlarged detail at FIG. 29). The clamps 204 comprise arecessed central portion 206 in which a pair of bosses 208 protrude, theM-shaped anchor member 210 of each float 202 nesting around the bosses208 (as in FIG. 28), with the end ears 212 of each clamp 204 beingbolted to the face of the panel 200, by bolts, certain of which areindicated at 214. Rows of holes, certain of which are indicated in FIG.26 and FIG. 27 at 216, are arranged longitudinally along the door .panel200 to provide interchangeability of lateral position of the variousfloats 202, one such row of holes being utilized when the edge portion44 is the upper edge and the other such row of holes being utilized whenthe edge portion 48' is the upper edge of the door. Said floats 202, aswill also be evident, can be used in any desired number to the extentpermitted by the number of mounting holes 216 available, and in anyarrangement along a row of holes, so that a degree of adjustability isalso provided as to the center of buoyancy and extent of buoyancycontributed by the floats 202.

The ballast means employed in the form of door shown at FIGS. 26-29comprises a plurality of weights 218 in the form of flat bars which canbe constituted of lead or cast iron or other heavy metal and which areinsulated from the panel by rubber pad 218 and rubber flanged bushing218" encircling the bolt 220, if the panel 200 and the weights are ofdissimilar metals. Said weights 218 can be stacked, in any desirednumber and can be employed as either a stack set or in a plurality ofstacks, each stack being bolted to the door panel 200 just inboard ofthe panel edging, the manner of mounting suitably involving a pluralityof bolts 220, each passing through a longitudinally extending slot 222.The slots 222 enable adjustable placement of the weights longitudinallyof the door panel 200 at any desired location. The said slots 222 areprovided in laterally opposite rows so that the ballast weight 218 canbe reversed in position on the door (along with the floats 202) when thedoor is inverted.

FIGS. 30-34 illustrate still another form of door embodying certainfeatures of the present invention. In FIGS. 30-34, the door panel 230 isprovided with a rubber or like edging 232 extending continuously aroundthe door, the edging 232 preferably being substantially circular inlateral cross-section except along the rear edge where cutouts 234, 236are provided to reduce drag. The manner of interconnection of the rubberor like edge 232 to the panel 230 is identical to the manner ofconnection characteristic of the panel-to-edging illustrated at FIG. 7.Ballasting means such as bar 238 is mounted inboard of the lower edge ofthe door, as shown at FIG. 31, the mounting being by means of a seriesof bolts 240 arranged in a row of holes 242 (FIG. 32). A laterallyopposite row of upper holes 244 permit reverse placement of the ballastmeans 238 when the door is inverted. The ballast means 238 may comprisea single bar, as shown, or a plurality of stacked bars, or a substitutelarger or smaller bar, so as to be to a degree adjustable in the mannercontemplated by the present invention.

In the form of door shown at FIGS. 30-34, the particular bridlearrangement and hookup arrangements for rigging the door with respect tothe towing warp T and the sweep lines SL, and the manner of invertingthe bridle assembly, are essentially disclosed in my US.

22. A TRAWL DOOR COMPRISING A BODY INTENDED TO BE UPRIGHT IN USE AND TORIDE ALONG ITS LOWER EDGE UPON THE BOTTOM, MEANS FOR SECUREMENT OF ATOWING WARP TO SAID BODY, AND MEANS FOR SECUREMENT OF SWEEPLINE MEANS TOSAID BODY, TO DISPOSE IT AT A GIVEN ANGLE OF ATTACK, IN USE, AN EDGINGOF RESILIENT, RUBBER-LIKE MATERIAL HAVING HIGH EXTENSIBILITY ANDFORCIBLE QUICK RETRACTION, SUCH RUBBERLIKE EDGING BEING SECURED ABOUTSAID BODY AND BEARING AT ITS LOWER PORTION UPON THE BOTTOM, ORALTERNATIVELY A ITS ORIGINALLY UPPER PORTION UPON REVERSAL OF THE DOORTOP FOR BOTTOM, AND A BALLAST WEIGHT REMOVABLY SECURED ALONG AND ABOVETHE EDGE WHICH IS LOWAER, TO BALLAST THE DOOR INTO ITS UPRIGHT POSITION,IN USE, AND BY ITS POSITIONS TO BE PROTECTED AGAINST WEAR.